Tamper proof “security screws” and nuts have been used to prevent or frustrate vandals and petty thieves. These are used, for example, to secure wheel rims to automobiles or protect against unauthorized removal of license plates. Some security screws rely upon a screw head having an unusual shape that requires a special tool to be used. Other security screws may have an asymmetric one-way, clutch head design that allows for easy attachment but not for removal. Alternatively, a threaded cap requiring a special tool to remove the cap may be used to hinder access to a traditional screw, as shown for example in D621,254S.